Transfer or diverter mechanisms are often desirable in conveyor systems for transferring conveyed articles from one conveyor to another or to a work station or the like. Transfer mechanisms range in complexity from simple barrier type diverters which deploy an arm diagonally across the main conveyor, through linear diverters wherein a bumper extends across the conveyor and pushes the article off one conveyor to another, to pop-up diverters of various kinds which are extended above the transfer surface of the conveyor to engage an article thereon for diversion purposes.
A desirable characteristic of a transfer mechanism on a powered conveyor is to have transfer elements on the mechanism driven by the same source of drive as the main conveyor to avoid the expense of a separate transfer drive motor. When the transfer mechanism has to be lifted into contact with articles on the main conveyor, complications arise from the need to maintain driving engagement between a main conveyor drive member and the transfer element. When belts are employed to transfer drive from a main conveyor drive member and a transfer element, a typical power takeoff arrangement pivots a frame supporting the transfer element such that the takeoff belt is pivoted about the rotational axis of the conveyor drive member. This avoids stretching the takeoff belt. In other arrangements, the takeoff belt is loose in a nondivert position of the transfer frame and becomes taut when the transfer frame is lifted to contact an article to be diverted. In still other arrangements, the takeoff belt is allowed to stretch.
Line shaft driven roller conveyors present particular problems when transfer mechanisms are driven by belts engaged with the line shaft. In a line shaft driven roller conveyor, power is transmitted from a rotary motor to conveyor rollers by an elongated line shaft extending the length of the conveyor. Small endless belts, or 0-rings, transmit rotation from the line shaft to the rollers. When belts are employed to transmit rotation, incidents occur in which the belts may be broken or stretched to a degree that they no longer frictionally engage the members between which rotation is to be transferred. Because of the length of some line shafts and the number of support bearings required therefor, removal of such line shafts for maintenance reasons is desirably minimized because of the labor and downtime involved.
In a conveyor with drop-in type rollers driven by a line shaft, a common practice is to provide extra roller driving belts on the line shaft to avoid displacing the line shaft merely to replace a roller driving belt. In the case of transfer mechanisms driven by a takeoff belt from a line shaft, it is desirable to configure the arrangement in such a manner that the belt can be replaced without removal of the line shaft.